Thanks to Paul Crockford for the tip: There is an excellent Easter Egg in Word 97 called "Word Pinball" which is, indeed, a simple Pinball game. Here's how you access it:

  1. Start Word 97 and open a new document.
  2. Type in the word "Blue" (no quotes).
  3. Select the word, and then click Format-->Font. Change it to bold and change the color to Blue, then click OK.
  4. Add a space after the word Blue.
  5. Choose Help-->About Microsoft Word.
  6. Hold down Ctrl + Shift and click the Word icon on the left side of the dialog box.
  7. The game appears. Use Z and M to work the flippers and Esc to end the game.
According to Paul, it runs on NT 3.51 SP5, NT4.0 SP3 and all versions of Windows 95. I tested it on Windows 98 and it works fine there as well. Enjoy